That will require a knowledge of at lease CSS coding. And the first thing to do will be to create a child theme with at least a style.css in it.

Note that this is a Bootstrap based theme and the width is governed by the container element which is set at 940px. You can start by copying that in to your child theme and then adjusting to your needs.

You must also consider that there @media factors at play to so you'll need to look at those and adjust for your needs.

Hope that helps to get you started :)

P.S. I believe the other topic is now resolve - if you could kindly mark it as such will appreciate it :)

Not a good idea and not recommended! - when the theme is update you will loose all of your changes. And as you can see from the theme we personally do not edit the Bootstrap.css but copy what we need to adjust/change over to the custom.css and do our edits there.

Simple steps:
1) Create a folder named strapvert-child
2) Copy style.css from main theme and add to your folder then add the following just underneath the Version number:
Template: strapvert
3) Go in to the css folder, open bootstrap.css and copy everything in to your new style.css
4) Open custom.css and copy everything and paste right at the bottom of your style.css

Now you can edit anything and everything to your hearts content :)

But....Do all your editing/modification on a production server and not the live. Once you are happy with your changes upload your child theme and activate and enjoy your handy work :)